1. Field of the Invention
This invention relates to an apparatus and a method for providing localised heat transfer (either for cooling or for heating a body).
2. Description of Related Art
Although the present invention will be described herein with particular reference to the chilling of a beverage, it finds much wider application. For example, quantities of paint (or similar material) could be kept warm so that they may be applied more readily; localised chilling may be provided at supermarket check-outs to keep foodstuffs (such as ice-cream) cold.
Referring now to the treatment of beverages, it is desirable that some beverages, particularly though not exclusively beers, lagers and milk, are chilled before they are consumed. Beverages are frequently dispensed from taps and it is sometimes desirable that such tap-dispensed beverages are chilled before (and/or as) they are dispensed.
Previous cooling systems for chilling tap-dispensed beverages, have comprised large chilled rooms into which barrels of the beverage are placed and allowed to equilibrate. Once the temperature of the barrel is in equilibrium with that of the room, the contents will have been chilled to an appropriate temperature. Further cooling has sometimes been provided in the vicinity of the dispensing taps to ensure that the beverage is dispensed at the optimum temperature.
For large establishments having a number of beverages on tap, the known arrangement requires that a large chilled room is provided. This is expensive to run and maintain and moreover the known cooling systems have generally used, as the cooling medium, hydrocarbon-derived gases, which can be harmful if vented to the atmosphere.
The Applicants have now devised a method of and apparatus for cooling beverages at the point of dispensing (in addition to or in place of cooling at the point of storage). Advantages of the method and apparatus of the present invention have been found to include:
(i) Reduced energy costs;
(ii) Environmentally more acceptable;
(iii) Reduction of the space required for chilling drink at the bar and therefore more space for stock;
(iv) Accurate temperature control and cooling at the dispensing point.
According to a first aspect of the present invention, there is provided a method of localised heat transfer to or from a container in which a cooling/heating unit including at least one Peltier junction is brought into proximity with the container and a heat transfer means is operatively associated with the cooling/heating unit, whereby either heat is removed from the unit (should heat be removed from the container) or heat is provided to the unit (should heat be supplied to the container).
Thus, a single cooling/heating unit can be provided which can be placed adjacent to a container and the container can be heated or cooled as desired.
According to a second aspect of the invention, there is provided a cooling apparatus comprising a beverage containment means, one or more cooling units, a cooling means, a venting means and a power supply means, the or each cooling unit including at least one Peltier junction and being placed adjacent the beverage containment means, the cooling means being adapted, in use, to remove heat from the container, the venting means being adapted, in use, to remove heat from the cooling means and vent it to the atmosphere and the power supply means being connected to the or each cooling unit and being adapted, in use, to power the or each Peltier junction.
This has the advantage that a self-contained unit is provided which can be used to chill the beverage containment means (rather than relying on a chilled room as was previously the case).
The apparatus of the present invention can also be used out-of-doors; since cooling is not being performed in an enclosed environment (a room), the location of the beverage containment means has no significance.
Further, the overall cost of the cooling system is reduced. If a new hotel, bar, restaurant, or the like is being set up, the capital outlay for the known cooling systems would be very high. A cooling system according to the present invention can be developed and/or extended as required.
Preferably, insulating means are provided which insulate the beverage containment means from its surroundings. This has the advantage that heat is not as readily absorbed by the beverage from the surroundings. Energy consumption should therefore be reduced when compared to a system not having insulating means.
The beverage containment means may comprise a barrel (or similar bulk storage container) and a delivery means associated therewith.
The delivery means may comprise a duct, pipe or the like, such apparatus being well known to those skilled in the relevant art. The delivery means may additionally be provided with further cooling means (such as a water-jacket), especially insulated xe2x80x9cPythonxe2x80x9d tubing.
The cooling unit may be placed in association with the barrel or it may be placed in association with the delivery means. This allows flexibility in the arrangement of the system.
In a preferred embodiment, more than one cooling unit is provided; at least one in association with the barrel and at least one in association with the delivery means.
Most preferably, the cooling unit provided in association with the delivery means is located at or near an end portion of the delivery means adjacent to where the beverage is dispensed.
The beverage may be a beer, a lager, a stout, a cider, a soft drink, or any other such beverage customarily dispensed from taps in public houses, restaurants, hotels, and similar establishments.
Preferably, a pumping means is provided to pump the beverage from the barrel through the delivery means to the dispensing point.
The cooling means may consist essentially of a cooling fluid, preferably water. Other fluids, such as hydrocarbon-derived gases, may be used. Fluids are relatively easy to handle and to use as coolants. It is particularly advantageous to use water as the cooling fluid as it is cheap, readily available, non-toxic, and non-polluting.
The cooling fluid may be continuously re-circulated so that the system is economic in its use of coolant.
The venting means may comprise a radiator, which is a particularly convenient way of loosing heat to the atmosphere. The radiator may be fan-assisted, thus providing a more compact venting means for the throughput of heat required.
Preferably the power supply means comprises a mains-fed transformer, thus providing a relatively secure source of power. The power supply means could alternatively or additionally (for example as a back-up supply) comprise one or more batteries.
The transformer can preferably provide 24V DC from a mains supply.
The apparatus may be adapted, in use, to deliver beverages chilled to a selectable temperature, for example xe2x88x9212xc2x0 C. to +12xc2x0 C. Normal temperatures at which beverages are dispensed are in the range +2xc2x0 C. to +8xc2x0 C.). It is desirable to be able to vary the temperature at which the beverage can be dispensed, so that the same apparatus can be used to dispense a variety of different beverages.
Preferably the pressure of the cooling fluid is less than 2.5 bar.
In an embodiment having more than one cooling unit, the cooling fluid may flow through each of the cooling units in turn. This has the advantage that only one cooling means is required per apparatus (as opposed to one for each cooling unit) thus making the apparatus much more cost-effective.
Preferably, the insulating means comprises a jacket which is adapted, in use, to surround the barrel. The jacket may have an opening means to allow the barrel to be inserted into the jacket.
The cooling apparatus may be manufactured from food-grade materials, possibly in accordance with prescribed (e.g. European) standards. This allows the beverage to contact the cooling apparatus and remain consumable.
The Peltier junction may comprise two regions of dissimilar types of semiconductor, such as an n-doped region and a p-doped region. Using dissimilar semiconductor materials in this manner provides suitable properties for the junction.
Preferably, each cooling unit comprises a thermoelectric module consisting of a plurality of p-type and n-type conductivity elements, the elements being held between a pair of ceramic plates or other insulating material. On passage of a current through the conductivity-elements, one of the plates acts as a heat-absorbing (cooling) surface and the other plate acts as a heat-releasing (heating) surface.
According to a third aspect of the invention there is provided a method of cooling a beverage comprising placing a cooling unit adjacent a containment means to remove heat from a beverage contained within the containment means, the cooling unit including at least one Peltier junction adapted to cause a cooling means to remove heat from the junction and to vent the removed heat to the atmosphere.
Such a method is advantageous since it is much more efficient than known techniques of cooling a beverage.
Preferably the method comprises cooling the beverage in the containment means from an ambient temperature to a chilled temperature by using the cooling unit and subsequently maintaining the beverage at the chilled temperature. This has the advantage that the cooling of the beverage does not need to be completely performed as the beverage is dispensed. Thus, the power required for the cooling unit can be reduced.
The method may comprise cooling the beverage from an ambient temperature of 25-35xc2x0 C. down to the chilled temperature of 10xc2x0 C. or lower. For example, the chilled temperature may be set to be 8xc2x0 C., or 6xc2x0 C., or 4xc2x0 C., or 2xc2x0 C.
Preferably, beer can be dispensed from the beverage containment means through a delivery means and the delivery rate may be at least 600 cm3 per minute. More preferably, the delivery rate may be about 1200 cm3 per minute and most preferably is at least 2400 cm3 per minute. Of course, the flow rate could be higher, perhaps 3000 cm3 or 4000 cm3 per minute. It has been found that these flow rates provide a convenient rate at which to dispense a beverage.
The method may further comprise continuously dispensing a beverage from a beverage containment means.
The beverage in the containment means may be cooled from the ambient temperature to the chilled temperature in from 6 to 14 hours, dependent on the starting temperature.
According to a fourth aspect of the invention there is provided the use of a cooling unit including at least one Peltier junction to cool a beverage.
The present invention will be illustrated, merely by way of example, in the following description and with reference to the accompanying drawings.